Motorola Alternator

I have a 1970 cj5, 134 fhead. I'm no electrical genius, and last Fall I kept getting a dead battery. had a friend that is an electromechanical engineer come over with his testing gizmo's. we (he) determined that the alternator was good, but nothing was telling it to turn on, and return power to the batter. so I installed a ballast resistor, and a voltage regulator, and it seemed to fix the issues. well, now I got a dead battery again. I called him up said hey, I am having battery problems again. he came over with all of his stuff, and we found through testing that the alternator is not charging the battery. the alternator is great, and just right for me, but the diodes are shot internally. he thought since we hooked everything up properly, the weakest link broke,m and that was the diodes. He wants me to buy the diodes, and we will install them in my 40 something year old alternator.

my question is, aren't I better off just buying a brand new alternator? I replace diodes, then the bearings go, etc... what do you guys think?

 

I wouldn't replace a motorola alternator . just switch over to a delco 10si alternator . no outside regulator required

 

X2.

 

you wouldn't replace it WITH a Motorola?

 

10si have much higher output and are very simple to install and are cheap and plentiful. I have a dauntless, but it had the same Motorola originally.

 

10si or 12si alternator on dauntless

 

One of the first things I do on most Jeeps is to put on a 10 (or 12 si if running an electric fan)

 

If your trying to keep your Jeep stock, rebuild (or just replace the diodes) to keep it all as it came new. If you just want function and depenability, swap over to a Delco with internal regulator.
Don't toss that Motorola! Some of us out there like things original, and the old units are getting harder to come by. I could even be interested.
-Donny

 

X2......I had the original 35-amp Motorola on my V6 rebuilt, and got a new repro external voltage regulator from Walck's. It seems to charge the battery normally, even pushing a 300W stereo.

Motorola also made a 55-amp version of the same alternator that's available as a rebuild. Here's a 55-amp Motorola for less than $50 that's been rebuilt by AC Delco: More Information for ACDELCO 3342209

 

I to have a Delco one wire on my '69 cj and that is great,but as said some times we want original on our classic vehicle. Just had my 35 amp Motorola rebuilt and works great and looks correct for my '71 Renegade II . Nothing wrong with staying stock. It's your jeep.

 

I used the Motorola mounting bracket and put a GM one wire on it by cutting about an inch off the back side of the one wire so the belt lines up with the crank pulley, and made a spacer for the tensioning arm. It has worked for 10 years now and no problem. There is a 5/8" pulley for the one wire available so you can use the right belt on the front crank pulley. Good luck.

 

so, my local autopart store doesn't have a 37 amp replacement for the Motorola, but they DO have a 55 amp unit available, to replace it.
whats different, other than 18 amps? the larger version just to accommodate more electrical doodads?

 

Yes. I just put in a new voltage regulator, may as well use it, right?

 

Ah. So the 55 is too big, ya say?

 

My bad. My alternator is actually 51 amps

 

The 55 amp Motorola is built in the same package as the 35 amp. A few internal parts are heavier gauge for additional current capabilities and the external plate has two output diodes instead of one. The regulator is a current limiter by sensing voltage so the regulator you have will work with the 55 amp.